A fourth dose of the Pfizer-BioNTech or Moderna vaccine was insufficient to prevent Covid-19, according to preliminary data from a trial in Israel released Monday.
A team from Sheba Hospital, near Tel Aviv, initiated a clinical trial at the end of December, vaccinating 154 caregivers with a fourth Pfizer dose and 120 other volunteers with a fourth Moderna dose.
“These are very preliminary results. This is before any publication, but we give it because we understand the urgency of the public to obtain all possible information on the fourth dose ”, said Dr. Gili Regev-Yochay, Director of Infection Prevention and Control Unit at Sheba Medical Center.
“We’ve had a Pfizer vaccine follow-up for two weeks now, and we’ve only had a Moderna vaccine follow-up for a week at this point. And what we see is that the Pfizer vaccine, after two weeks, you see an improvement or an increase in the number of antibodies and neutralizing antibodies – a pretty nice increase. It’s even a bit higher than what we had after the third dose “, she added.
Last week, European Union regulators warned that frequent booster shots of Covid-19 could weaken the immune system and may not be feasible. Israel becomes a test case for the fourth vaccine as cases reach a record.
Israel began rolling out the fourth dose of the vaccine to those over 60 and immunocompromised in late December amid a spike in cases. Since then, more than half a million Israelis have received the extra dose, according to the Health Ministry.
The decision to give the fourth vaccine to the most vulnerable was the right one, Regev-Yochay told a virtual press conference, because it could have provided an additional advantage against omicron. But the results did not support a wider deployment to the entire population, believes the expert.
Omicron is already dominant in many countries and can also infect those who have been vaccinated or previously infected with earlier versions of the virus. L
Early studies, however, show that it is less likely to cause serious illness than Delta. Vaccination and a booster still offer strong protection against serious illness, hospitalization and death.
On Tuesday, the Israeli government said it was reducing the mandatory quarantine period from seven days to five days to help keep the economy going.
“This decision will allow us to continue to preserve public health on the one hand and to keep the economy going at the moment on the other hand, even if it is difficult, so that we can get through this wave safely”, said the country’s Prime Minister Naftali Bennett. .